These ForgeFix TechFast Window Screws Countersunk Single Thread are suitable for window and door frame construction and hardware fixing in PVCu They have a countersunk head with TORX® compatible recess Their sharp point allows self-piercing These screws are fire resistant and are protected by Elementech corrosion resistant coating which has been salt spray tested to 1000 hours They comply with EU safety health and environmental requirements TORX® compatible impact bit included